Methodologies for the extraction of phenolic compounds from environmental samples: new approaches

Eco-friendly spectrophotometric methods for concurrent analysis of phenol, 2-aminophenol, and 4-aminophenol in ternary mixtures and water samples: assessment of environmental sustainability

Recently, there has been a high demand for green procedures in analytical chemistry, particularly those utilizing eco-friendly solvents. In this context, three feasible derivative UV spectrophotometric methods namely, derivative ratio-zero crossing spectra (DRZCS), double divisor ratio spectra (DDRS), and successive derivative subtraction coupled with constant multiplication (SDS-CM) were developed to quantify a ternary mixture of phenol (P), 2-aminophenol (2-AP), and 4-aminophenol (4-AP) in real water samples simultaneously, using ethanol as a solvent. The established methods demonstrated a good linear range, covering 2-60 μg mL-1 for P and 2-50 μg mL-1 for 2-AP and 4-AP, in all approaches with a high correlation coefficient (R2 ≥ 0.9995). In compliance with ICH guidelines, the methods exhibited acceptable precision and accuracy, as indicated by good spike recovery with low relative standard deviations. The eco-friendliness of the UV spectrophotometric approach was assessed using analytical eco-scale (AES), analytical greenness (AGREE), and analytical greenness metrics for sample preparation (AGREEprep). These evaluations confirmed the eco-friendliness of the proposed methods in terms of solvents, energy consumption, and waste generation. The proposed procedure proved to be efficient in quantifying each component in laboratory-synthesized mixtures and real water samples, thanks to its simplicity, accuracy, sensitivity, and cost-effectiveness.

Investigation of Health Effects of Major Phenolic Compounds in Foods: Extraction Processes, Analytical Approaches and Applications

The escalating costs of healthcare services and a growing awareness of personal health responsibilities have led individuals to explore natural methods alongside conventional medicines for health improvement and disease prevention. The aging global population is experiencing increased health needs, notably related to conditions like diabetes, heart disease, and hypertension. Lifestyle-related diseases, poor dietary habits, and sedentary lifestyles underscore the importance of foods containing nutrients that can aid in preventing and managing these diseases. Phenolic compounds, a fundamental group of phytochemicals, are prominent in the chemical diversity of the natural world and are abundant in functional foods. Widely distributed in various plant parts, these compounds exhibit important functional and sensory properties, including color, taste, and aroma. Their diverse functionalities, particularly antioxidant activity, play a crucial role in mitigating cellular oxidative stress, potentially reducing damage associated with serious health issues such as cardiovascular disease, neurodegenerative disea23ses, and cancer. Phenolic compounds exist in different forms, some combined with glycosides, impacting their biological effects and absorption. Approximately 8000 polyphenols isolated from plants offer significant potential for natural medicines and nutritional supplements. Therefore, their extraction process and selective and sensitive food determination are very important. This review focuses on the extraction processes, analytical methods, and health effects of major phenolic compounds in foods. The examination encompasses a comprehensive analysis of analytical approaches and their applications in elucidating the presence and impact of these compounds on human health.

Phenolic compounds occurrence and human health risk assessment in potable and treated waters in Western Cape, South Africa

Phenolic pollutants from industrial and agricultural activities pose a major threat to the world's potable water supply. The persistent micro-pollutants often find their way into drinking water sources with possible adverse human health implications. In this study, bottled water, tap water, and wastewater treatment plant (WWTP) effluent samples from the Boland region of the Western Cape, South Africa were assessed to determine 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) levels using HPLC/DAD instrumentation. The selected area is known for its vast agricultural ventures and wineries. Evaluation of the human health risk (cancer risk) for the pollutants was conducted using the hazard quotient (HQ). The Ames mutagenicity test was also conducted using the Salmonella typhimurium T98 and T100 strains and the S9 activation enzyme. Trace levels of the phenolics were detected in the samples with a range of 9.32 × 10-7-1.15 × 10-4 mg/L obtained for 4-CP, and 8.80 × 10-7-1.72 × 10-4 mg/L recorded for 2,4-DCP. Both compounds had levels below the limit of 0.01 mg/L prescribed by South African legislation. The assessed HQ for the phenolic concentrations indicates a low level of potential ecological risk and none of the samples had a cancer risk value that exceeded the regulatory limit. The possibility of the analyzed samples causing cancer is unlikely, but non-carcinogenic adverse effects were found. Strong mutagenicity was observed for the T98 strains with a potential ability to cause mutation toward the insertion or deletion of a nucleotide. The T100 bacterial strain showed very slight mutagenicity potential, however, it is unlikely to cause any mutation. The levels of phenolics in the potable water samples may pose a significant threat to human health. Hence, screening persistent organic chemicals in potable water sources and evaluating their potential human health effects is pertinent to prevent associated health challenges.

Quantitative analysis of naphthalene, 1-naphthol and 2-naphthol at nanomol levels in geothermal fluids using SPE with HPLC

Naphthalene (NAP), 1-naphthol (1-NAP) and 2-naphthol (2-NAP) are the thermal decomposition products of naphthalene sulfonates making them potentially new geothermal reservoir permeability tracers, however, to date, no sensitive and fast detection method for these compounds has been developed. In order to facilitate sensitive and rapid analysis of these compounds in geothermal brines and associated steam condensates, a high-performance liquid chromatography (HPLC) method combined with solid-phase extraction (SPE) has been developed.•A method for determination of naphthalene, 1- and 2-naphthol from brines has been developed.•These compounds have been detected in steam samples from three New Zealand geothermal fields.•As breakdown products of NDS/NSA, these compounds have potential use as geothermal tracers.

Elevating Cereal-Based Nutrition: Moringa oleifera Supplemented Bread and Biscuits

Enhancing the nutritional value of commonly consumed, cost-effective staple foods, such as bread and biscuits, by fortifying them with Moringa oleifera leaf powder (MOLP) and its phenolic-rich extract holds substantial potential for addressing malnutrition. This study evaluated the phenolic extract from MOLP obtained through Soxhlet extraction, focusing on its antioxidant, antibacterial, and antidiabetic properties. The resulting extract exhibited a total phenolic content (TPC) of 138.2 mg of gallic acid equivalents/g. The ABTS and DPPH assays presented IC50 values of 115.2 mg/L and 544.0 mg/L, respectively. Furthermore, the extract displayed notable α-amylase inhibition and no cytotoxicity towards human fibroblasts. The primary phenolic compounds identified were catechin, epicatechin, and caffeic acid. Subsequently, MOLP and its extract were incorporated into bread and biscuits, replacing 5% of wheat flour, resulting in fortified functional foods. The fortified products exhibited improved TPC and antioxidant activity compared to the non-fortified foods. Furthermore, they displayed the ability to inhibit microbial growth, leading to an extended shelf life. Sensory analysis indicated that the products incorporated with the extract were preferred over those with MOLP. These results have demonstrated the viability of using MOLP and its phenolic-rich extract as an environmentally sustainable strategy for enhancing the quality of cereal-based products.

A review of natural plant extracts in beverages: Extraction process, nutritional function, and safety evaluation

The demand for foods and beverages with therapeutic and functional features has increased as a result of rising consumer awareness of health and wellness. In natural, plants are abundant, widespread, and inexpensive, in addition to being rich in bioactive components that are beneficial to health. The bioactive substances contained in plants include polyphenols, polysaccharides, flavonoids, aromatics, aliphatics, terpenoids, etc., which have rich active functions and application potential for plant-based beverages. In this review, various existing extraction processes and their advantages and disadvantages are introduced. The antioxidant, anti-inflammatory, intestinal flora regulation, metabolism regulation, and nerve protection effects of plant beverages are described. The biotoxicity and sensory properties of plant-based beverages are also summarized. With the diversification of the food industry and commerce, plant-based beverages may become a promising new category of health functional foods in our daily lives.

Biochemical analysis, photosynthetic gene (psbA) down–regulation, and in silico receptor prediction in weeds in response to exogenous application of phenolic acids and their analogs

Chemical herbicides are the primary weed management tool, although several incidences of herbicide resistance have emerged, causing serious threat to agricultural sustainability. Plant derived phenolic acids with herbicidal potential provide organic and eco-friendly substitute to such harmful chemicals. In present study, phytotoxicity of two phenolic compounds, ferulic acid (FA) and gallic acid (GA), was evaluated in vitro and in vivo against three prevalent herbicide-resistant weed species (Sinapis arvensis, Lolium multiflorum and Parthenium hysterophorus). FA and GA not only suppressed the weed germination (80 to 60% respectively), but also negatively affected biochemical and photosynthetic pathway of weeds. In addition to significantly lowering the total protein and chlorophyll contents of the targeted weed species, the application of FA and GA treatments increased levels of antioxidant enzymes and lipid peroxidation. Photosynthetic gene (psbA) expression was downregulated (10 to 30 folds) post 48 h of phenolic application. In silico analysis for receptor identification of FA and GA in psbA protein (D1) showed histidine (his-198) and threonine (thr-286) as novel receptors of FA and GA. These two receptors differ from the D1 amino acid receptors which have previously been identified (serine-264 and histidine-215) in response to PSII inhibitor herbicides. Based on its toxicity responses, structural analogs of FA were also designed. Four out of twelve analogs (0.25 mM) significantly inhibited weed germination (30 to 40%) while enhancing their oxidative stress. These results are unique which provide fundamental evidence of phytotoxicity of FA and GA and their analogs to develop cutting-edge plant based bio-herbicides formulation in future.

Use of tyrosinase-inorganic salt hybrid nanoflowers and tyrosinase-MOF hybrid composites for elimination of phenolic pollutants from industrial wastewaters

Removal of phenolic pollutants from industrial wastewaters is always an important practical problem. Use of enzymes for dephenolization provides a green solution. In this work, enzymatic methods were developed by employing mushroom tyrosinase immobilized as enzyme-Cu₃(PO₄)₂ hybrid nanoflowers and enzyme-metal organic framework (i.e., ZIF-8 and HKUST-1) hybrid composites, which were shown to be superior to processes mediated by tyrosinase immobilized on other supports in both dephenolization efficiency and reusability. Comparatively, tyrosinase@Cu₃(PO₄)₂ and tyrosinase@HKUST-1 were better than tyrosinase@ZIF-8 in both specific activity and dephenolization efficiency. Typical phenolic pollutants, including 3 monophenols (phenol, p-cresol, p-chlorophenol) and 3 bisphenols (BPA, BPB, BPF), can be completely eliminated within 0.5-4 h. The dephenolization order was discussed based on the enzyme's substrate specificity. The operability and reusability of these hybrid biocomposites were highly improved by entrapping into alginate gels or by incorporating with modified magnetic Fe₃O₄ nanoparticles. Particularly, the magnetic biocatalyst was prepared via a facile one-pot/one-step de novo synthetic strategy, optimized by using response surface methodology (RSM). The as-prepared magnetic tyrosinase@mHKUST-1 retained a high dephenolization efficiency of 81% after 10 cycles and was effective for continuous dephenolization for at least 24 h. These hybrid biocomposites were also successfully applied to treatment of real industrial wastewater from a coke plant.

Rapid adsorption of triclosan and p-chloro-m-xylenol by nitrogen-doped magnetic porous carbon

Contamination of water resources with organic substances like phenolic fungicides is undesirable due to the improvement of living standards, the huge production of chemicals, the heavy consumption of daily chemical products, and the growth of the population. In this study, Co-based zeolitic imidazole framework-67 (ZIF-67(Co)) was synthesized using the "one-pot method," and the best Co-based N-doped magnetic porous carbon (Co-NPC) was prepared by ZIF-67(Co) carbonization in an atmosphere of N₂. The materials were tested using an X-ray diffractometer (XRD), scanning electron microscope (SEM), infrared spectroscopy (IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), N₂ adsorption-desorption, and magnetization analysis. These characterizations indicated that the Co-NPC was successfully prepared. With the original morphology of ZIF-67(Co) crystals, the Co-NPC also has good porosity, magnetic properties, and a large specific surface area. In water, Co-NPC-800 has a good adsorption capacity for triclosan (TCS) and p-chloro-m-xylenol (PCMX), which are kinds of aromatic fungicides. The adsorption of Co-NPC-800 on both reached equilibrium within 3 min, which is in accordance with the quasi-second-order kinetic model. At 298 K, the maximum adsorption capacity of Co-NPC-800 for TCS and PCMX was 163 and 39 mg·g^-1, respectively. The adsorption of TCS and PCMX by Co-NPC-800 is a spontaneous endothermic process with reduced entropy. The combination of Co-NPC-800 and phenols come from multiple actions of electrostatic, π-π, and hydrogen bond effects. Moreover, Co-NPC-800 can be regenerated through simple washing and can be reused at least three times by a magnet. The Co-NPC-800 has good porosity, large specific surface area, comparable adsorption capacity, rapid adsorption time, so it could be broadly used in sewage treatments and other environmental fields.

Ultrasound-assisted green extraction methods: An approach for cosmeceutical compounds isolation from Macadamia integrifolia pericarp

This study aimed was to examine the potential of several green extraction methods to extract cosmetic/cosmeceutical components from Macadamia integrifolia pericarps, which were a by-product of the macadamia nut industry. M. integrifolia pericarps were extracted by conventional solvent extraction process using 95% v/v ethanol and various green extraction methods, including infusion, ultrasound, micellar, microwave, and pulsed electric field extraction using water as a clean and green solvent. The extracts were evaluated for total phenolic content using Folin-Ciocalteu method.The antioxidant activities were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing/antioxidant power, and ferric-thiocyanate method. The anti-skin ageing activities were investigated by means of collagenase, elastase, and hyaluronidase inhibition using enzyme-substrate reaction assay. The irritation profile of the extracts was evaluated by the hen's egg test-chorioallantoic membrane (HET-CAM) test. The results noted that ultrasound-assisted extraction yielded the significantly highest extract amount with the significantly highest total phenolic content (p < 0.05), especially when the extraction time was 10 min. The aqueous extract from ultrasound-assisted extraction possessed the most potent antioxidant and anti-skin ageing activities (p < 0.05). Its antioxidant activities were comparable to ascorbic acid and Trolox, whereas the anti-skin ageing activities were equivalent to epigallocatechin-3-gallate and oleanolic acid. Besides, the extract was safe since it induced no irritation in the HET-CAM test. Therefore, ultrasound-assisted extraction was suggested as an environmentally friendly extraction method for M. integrifolia pericarp extraction and further application in the cosmetic/cosmeceutical industries.

The effect of disinfectants and antiseptics on co- and cross-selection of resistance to antibiotics in aquatic environments and wastewater treatment plants

The outbreak of the SARS-CoV-2 pandemic led to increased use of disinfectants and antiseptics (DAs), resulting in higher concentrations of these compounds in wastewaters, wastewater treatment plant (WWTP) effluents and receiving water bodies. Their constant presence in water bodies may lead to development and acquisition of resistance against the DAs. In addition, they may also promote antibiotic resistance (AR) due to cross- and co-selection of AR among bacteria that are exposed to the DAs, which is a highly important issue with regards to human and environmental health. This review addresses this issue and provides an overview of DAs structure together with their modes of action against microorganisms. Relevant examples of the most effective treatment techniques to increase the DAs removal efficiency from wastewater are discussed. Moreover, insight on the resistance mechanisms to DAs and the mechanism of DAs enhancement of cross- and co-selection of ARs are presented. Furthermore, this review discusses the impact of DAs on resistance against antibiotics, the occurrence of DAs in aquatic systems, and DA removal mechanisms in WWTPs, which in principle serve as the final barrier before releasing these compounds into the receiving environment. By recognition of important research gaps, research needs to determine the impact of the majority of DAs in WWTPs and the consequences of their presence and spread of antibiotic resistance were identified.

Extraction Systems and Analytical Techniques for Food Phenolic Compounds: A Review

Phenolic compounds are highly valuable food components due to their potential utilisation as natural bioactive and antioxidant molecules for the food, cosmetic, chemical, and pharmaceutical industries. For this purpose, the development and optimisation of efficient extraction methods is crucial to obtain phenolic-rich extracts and, for some applications, free of interfering compounds. It should be accompanied with robust analytical tools that enable the standardisation of phenolic-rich extracts for industrial applications. New methodologies based on both novel extraction and/or analysis are also implemented to characterise and elucidate novel chemical structures and to face safety, pharmacology, and toxicity issues related to phenolic compounds at the molecular level. Moreover, in combination with multivariate analysis, the extraction and analysis of phenolic compounds offer tools for plant chemotyping, food traceability and marker selection in omics studies. Therefore, this study reviews extraction techniques applied to recover phenolic compounds from foods and agri-food by-products, including liquid-liquid extraction, solid-liquid extraction assisted by intensification technologies, solid-phase extraction, and combined methods. It also provides an overview of the characterisation techniques, including UV-Vis, infra-red, nuclear magnetic resonance, mass spectrometry and others used in minor applications such as Raman spectroscopy and ion mobility spectrometry, coupled or not to chromatography. Overall, a wide range of methodologies are now available, which can be applied individually and combined to provide complementary results in the roadmap around the study of phenolic compounds.

Innovative progress in graphene derivative-based composite hybrid membranes for the removal of contaminants in wastewater: A review

Graphene derivatives (graphene oxide) are proved as an innovative carbon materials that are getting more attraction in membrane separation technology because of its unique properties and capability to attain layer-to-layer stacking, existence of high oxygen-based functional groups, and generation of nanochannels that successively enhance the selective pollutants removal performance. The review focused on the recent innovations in the development of graphene derivative-based composite hybrid membranes (GDHMs) for the removal of multiple contaminants from wastewater treatment. To design GDHMs, it was observed that at first GO layers undergo chemical treatments with either different polymers, plasma, or sulfonyl. After that, the chemically treated GO layers were decorated with various active functional materials (either with nanoparticles, magnetite, or nanorods, etc.). By preparing GDHMs, properties such as permeability, porosity, hydrophilicity, water flux, stability, feasibility, mechanical strength, regeneration ability, and antifouling tendency were excessively improved as compared to pristine GO membranes. Different types of novel GDHMs were able to remove toxic dyes (77-100%), heavy metals/ions (66-100%), phenols (40-100%), and pharmaceuticals (74-100%) from wastewater with high efficiency. Some of GDHMs were capable to show dual contaminant removal efficacy and antibacterial activity. In this study, it was observed that the most involved mechanisms for pollutants removal are size exclusion, transport, electrostatic interactions, adsorption, and donnan exclusion. In addition to this, interaction mechanism during membrane separation technology has also been elaborated by density functional theory. At last, in this review the discussion related to challenges, limitations, and future outlook for the applications of GDHMs has also been provided.

Organic solvent extraction and spectrophotometric quantification of total phenolic content of soil

Phenolic compounds are regarded as the most abundant plant metabolites that are known to decompose progressively into soils, likened to other soil organic materials. Once assimilated into soils, they can control soil processes, including organic matter decomposition and nutrient cycling. Established that phenolic compounds can influence nutrients availability and soil quality, it becomes crucial to investigate into soil phenolics through the application of appropriate extraction technique and quantification of ​total phenolic content ​in soils. This study therefore aimed at utilizing ethanol, hexane and diethyl ether organic solvents to extract and quantify total phenolic content of soil, sampled from a vegetable growing area. Conventional organic solvent extraction method was employed to extract phenolics, while spectrophotometric technique was utilized to quantify total phenolic content. The highest extraction yield of 34.52% was achieved with ethanol followed by diethyl ether (28.23%) and hexane (25.47%). Interestingly, hexane, which had the least extraction yield, rather recorded the highest phenolics concentration of 5.50 ± 0.02 mgGAE/g, with ethanol producing a concentration of 2.04 ± 0.05 mgGAE/g and 3.82 ± 0.01 mgGAE/g for diethyl ether. The percent recovery, limit of detection (LOD) and limit of quantification (LOQ) of phenolic compounds were found to be 102%, 0.8 mg/g and 1.5 mg/g for ethanol; 96%, 0.6 mg/g and 1.2 mg/g for diethyl ether and 94%, 0.4 mg/g and 1.0 mg/g for hexane respectively. These results indicate that for an extraction efficiency and greater yield, the use of ethanol as solvent is preferred whereas extraction using hexane is suitable for total phenolics quantification. The findings of this study have provided a vital insight regarding the influence of organic solvents on the extractability and quantification of total phenolic content of soil.

Optimization of Pulsed Electric Field as Standalone "Green" Extraction Procedure for the Recovery of High Value-Added Compounds from Fresh Olive Leaves

Olive leaves (OLL) are reported as a source of valuable antioxidants and as an agricultural by-product/waste. Thus, a twofold objective with multi-level cost and environmental benefits arises for a "green" standalone extraction technology. This study evaluates the OLL waste valorization through maximizing OLL extracts polyphenol concentration utilizing an emerging "green" non-thermal technology, Pulsed Electric Field (PEF). It also provides further insight into the PEF assistance span for static solid-liquid extraction of OLL by choosing and fine-tuning important PEF parameters such as the extraction chamber geometry, electric field strength, pulse duration, pulse period (and frequency), and extraction duration. The produced extracts were evaluated via comparison amongst them and against extracts obtained without the application of PEF. The Folin-Ciocalteu method, high-performance liquid chromatography, and differential scanning calorimetry were used to determine the extraction efficiency. The optimal PEF contribution on the total polyphenols extractability (38% increase with a 117% increase for specific metabolites) was presented for rectangular extraction chamber, 25% v/v ethanol:water solvent, pulse duration (tpulse) 2 μs, electric field strength (E) 0.85 kV cm-1, 100 μs period (Τ), and 15 min extraction duration (textraction), ascertaining a significant dependence of PEF assisting extraction performance to the parameters chosen.

Assessment of persistent organic pollutants in soil and sediments from an urbanized flood plain area

Polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and phenolic compounds (PCs) are persistent organic compounds. Contamination of these potentially toxic organic pollutants in soils and sediments is most studied environmental compartments. In recent past, studies were carried out on PAHs, OCPs and PCs in various soils and sediments in India. But, this is the first study on these pollutants in soils and sediments from an urbanized river flood plain area in Delhi, India. During 2018, a total of fifty-four samples including twenty-seven each of soil and sediment were collected and analyzed for thirteen priority PAHs, four OCPs and six PCs. The detected concentration of ∑PAHs, ∑OCPs and ∑PCs in soils ranged between 473 and 1132, 13 and 41, and 639 and 2112 µg/kg, respectively, while their concentrations in sediments ranged between 1685 and 4010, 4.2 and 47, and 553 and 20,983 µg/kg, respectively. PAHs with 4-aromatic rings were the dominant compounds, accounting for 51 and 76% of total PAHs in soils and sediments, respectively. The contribution of seven carcinogen PAHs (7CPAHs) in soils and sediments accounted for 43% and 61%, respectively, to ∑PAHs. Among OCPs, p, p'-DDT was the dominant compound in soils, while α-HCH was found to be dominated in sediments. The concentrations of ∑CPs (chlorophenols) were dominated over ∑NPs (nitrophenols) in both the matrices. Various diagnostic tools were applied for the identification of their possible sources in soil and sediments. The observed concentrations of PAHs, OCPs and PCs were more or less comparable with the recently reports from various locations around the world including India. Soil quality guidelines and consensus-based sediment quality guidelines were applied for the assessment of ecotoxicological health effect.

Immobilisation of phosphonium-based ionic liquid in polysulfone capsules for the removal of phenolic compounds, with an emphasis on 2,4-dichlorophenol, in aqueous solution

Phosphonium-based ionic liquid immobilised in polysulfone capsules were prepared by the phase inversion technique for the adsorption of different phenolic compounds from aqueous solution. Some techniques, including Scanning Electron Microscopy (SEM), surface analysis by Brunauer-Emmett-Teller (BET), Fourier Transform Infrared Spectroscopy (FT-IR) and Thermogravimetric Analysis (TGA), were used to characterize the capsule and indicated that trihexyltetradecylphosphonium decanoate (ionic liquid) was successfully immobilised in polysulfone, the immobilisation was determined to be 63.29%. Adsorption tests showed that the developed capsules have the potential to remove varied phenolic compounds. For compounds 2,4-dichlorophenol (2,4-DCP) the best removal was achieved between pH 3.0 and 9.0. Temperature variation (25-70 °C) and sodium chloride concentration (0-1000 mg⋅L^-1) had no significant changes in adsorption, demonstrating the scope for using this adsorbent with real effluents. Adsorption kinetics demonstrated the mechanism occurs in second order, the Weber-Morris model delimited the intraparticle diffusion as the adsorption limiter. The Redlich-Peterson model was the isothermal analysis that best suited the experimental data, with a β value equal to 0.821 approaching the Langmuir model, which obtained a q_max of 404.50 mg⋅g^-1. Consequently, these results demonstrate that these capsules have potential application in the treatment of environmental pollution caused by phenolic compounds.

Effective Approach of Activated Jordanian Bentonite by Sodium Ions for Total Phenolic Compounds Removal from Olive Mill Wastewater

Olive mill wastewater (OMW) is nowadays considered a serious environmental problem, especially within the Mediterranean region. With this in mind, water shortages are also a very serious and prevalent concern in third world countries. The aim of this study is to investigate the feasibility of using Jordanian bentonite, a simple and natural clay, as a possible adsorbent to decrease the negative characteristics of raw OMW, as an approach to the development of a methodology that addresses the OMW problem without affecting freshwater resources. The purified bentonite was activated by sodium ions at room temperature. FTIR, XRD, TGA, and BET surface area measurements were performed. OMW was contacted with both purified and activated bentonite in the batch technique to figure out the optimum parameters for the adsorption process. Physiochemical parameters of OMW were measured before and after treatment. The maximum adsorption qm was found as 8.81 mg/g at 323 K for the total phenolic compounds. The Langmuir and Freundlich models were utilized to describe the equilibrium isotherms and both models fit well. The parameters of thermodynamic show that the adsorption process was feasible, spontaneous, and endothermic in nature. These promising results along with the sodium activation of bentonite significantly improve bentonite’s adsorption capacity.

Use of Pulsed Electric Field as a Low-Temperature and High-Performance “Green” Extraction Technique for the Recovery of High Added Value Compounds from Olive Leaves

Olive leaves (OLL), an agricultural waste by-product, are considered a significant bioresource of polyphenols, known as bioactive compounds. This study evaluates the pulsed electric field (PEF) technique for the extraction of polyphenols from OLL. The study parameters included a series of “green” solvents (ethanol, water as well as mixtures of them at a 25% step gradient) and different input values for the pulse duration of PEF. The phytochemical extraction degree was evaluated using total phenol concentration (Folin–Ciocalteu method) and high-performance liquid chromatography (HPLC) analyses, while the antioxidant activity was assessed using differential scanning calorimetry (DSC). The results obtained from the PEF extracts were compared with those of the extracts produced without the PEF application. The highest PEF effect was observed for aqueous ethanol, 25% v/v, using a pulse duration of 10 μs. The increase in the total polyphenols reached 31.85%, while the increase in the specific metabolites reached 265.67%. The recovery in polyphenols was found to depend on the solvent, the pulse duration of treatment and the structure of the metabolites extracted.

Determination of environmental properties and toxicity of octyl-dimethyl-para-aminobenzoic acid and its degradation products

Octyl-dimethyl-para-aminobenzoic acid (ODPABA) is one of compounds of emerging concern. It undergoes transformations under the influence of oxidizing or chlorinating agents and UV radiation forming products with different properties. There is very little experimental data concerning the environmental fate of ODPABA and its transformation products. Therefore, the purpose of the studies was to determine environmental parameters: water solubility, soil - water partition coefficient, octanol - air partition coefficient, bioconcentration factor as well as half-life in air, water and soil. Based on the results obtained, the persistence and migration possibilities of ODPABA and its transformation products in the aquatic environment were estimated. Moreover, the ecological toxicity of oxidation and chlorination products was investigated. Microtox®, Daphtoxkit F® and Artoxkit M® tests were used to determine toxicity. LC₅₀ for Fish and Daphnia magna was calculated by Ecosar module. Studies have shown that as a result of ODPABA transformations, chloroorganic products are formed, which are lipophilic, are bioconcentrated in organic matter, are characterized by significant environmental persistence, can spread over considerable distances and are toxic. Oxidation products have significantly smaller impact on the environment. They are characterized by higher water solubility, lower bioconcentration factor and are less toxic.

Porous thin-film molecularly imprinted polymer device for simultaneous determination of phenol, alkylphenol and chlorophenol compounds in water

A porous water-compatible molecularly imprinted polymer (MIP) coating using catechol as a pseudo-template and a water-soluble functional monomer (4-vinyl benzoic acid) with ethylene glycol dimethacrylate as the crosslinker was developed for extraction of phenols from environmental water samples. The MIP devices were combined with ultra high performance liquid chromatography with a photodiode array detector (UHPLC-PDA) suitable for the simultaneous determination of trace levels of phenolic compounds with a wide range of polarities -phenol, alkylphenols and chlorophenols- in seawater and produced water. Parameters that influence extraction efficiency (salinity, pH, polymer mass, desorption solvent, and desorption time) were optimized to give method detection limits (LOD) ranging from 0.1 to 2 μg L^-1 and linearity (R²>0.99) over at least three orders of magnitude for the hydrophobic phenols (e.g., 0.5-1000 μg L^-1 for 2,4,6-trichlorophenol) and ~2 orders of magnitude for the light phenols (e.g., 10-120 μg L^-1 for phenol, 5-120 μg L^-1 for methylphenols and 2-chlorophenol, 0.5-120 μg L^-1 3-methyl-4-chlorophenol and 2,4-dichlorophenol). The recoveries from authentic spiked samples ranged from 85 to 100% with %RSDs of 0.2-14% for seawater and 81-107% with %RSD of 0.1-11% for produced water. The resulting MIP-based extraction requires no pre-conditioning of the sorbent, and because the required sample size is small and sample manipulation is limited, the method is easy to multiplex for high throughput sample processing.

Phenolic compounds seasonal occurrence and risk assessment in surface and treated waters in Minas Gerais-Brazil

This study provided a monitoring of phenolic compounds occurrence in a river and in its treated water by a conventional water treatment plant (WTP) throughout a year-period, in Minas Gerais - Brazil. Furthermore, the environmental risk (hazard quotient - HQ), the human health risk (margin of exposure - MOE), and the cancer risk were calculated for the compounds. The results indicated that sixteen out of the seventeen investigated phenolic compounds were detected at some point during the sampling campaign. The most frequent compounds in the raw surface water were 2,3,4-trichlorophenol (234TCP), 2,4-dimethylphenol (24DMP), and 4-nitrophenol (4NP), whereas in treated water were 4NP and bisphenol A (BPA). In addition, the highest total concentration values were corelated to the months in which there was less precipitation, demonstrating that the presence of this micropollutants may be subject to seasonality. From the treated water results, it was not possible to state the efficiency of the conventional WTP in eliminating the phenols, since in some samples the phenolic compounds were totally removed and in others their increase or formation occurred. Regarding to the risk assessments, most of the evaluated compounds were considered highly toxic to some trophic level and posed a significant human health risk. Additionally, the risk reduction of phenolics using conventional WTP was low. The sixteen phenols contamination in surface and drinking waters appears to be subject to seasonality. Besides that, an alarming risk for environment and human health was identified.

Hydrolase CehA and a Novel Two-Component 1-Naphthol Hydroxylase CehC1C2 are Responsible for the Two Initial Steps of Carbaryl Degradation in Rhizobium sp. X9

Carbaryl is a widely used carbamate pesticide in agriculture. The strain Rhizobium sp. X9 possesses the typical carbaryl degradation pathway in which carbaryl is mineralized via 1-naphthol, salicylate, and gentisate. In this study, we cloned a carbaryl hydrolase gene cehA and a novel two-component 1-naphthol hydroxylase gene cehC1C2. CehA mediates carbaryl hydrolysis to 1-naphthol and CehC1, an FMNH₂ or FADH₂-dependent monooxygenase belonging to the HpaB superfamily, and hydroxylates 1-naphthol in the presence of reduced nicotinamide-adenine dinucleotide (FMN)/flavin adenine dinucleotide (FAD), and the reductase CehC2. CehC1 has the highest amino acid similarity (58%) with the oxygenase component of a two-component 4-nitrophenol 2-monooxygenase, while CehC2 has the highest amino acid similarity (46%) with its reductase component. CehC1C2 could utilize both FAD and FMN as the cofactor during the hydroxylation, although higher catalytic activity was observed with FAD as the cofactor. The optimal molar ratio of CehC1 to CehC2 was 2:1. The K_m and K_cat/K_m values of CehC1 for 1-naphthol were 74.71 ± 16.07 μM and (8.29 ± 2.44) × 10^-4 s^-1·μM^-1, respectively. Moreover, the enzyme activities and substrate spectrum between CehC1C2 and previously reported 1-naphthol hydroxylase McbC were compared. The results suggested that McbC had a higher 1-naphthol hydroxylation activity, while CehC1C2 had a broader substrate spectrum.

Transformation of Contaminants of Emerging Concern (CECs) during UV-Catalyzed Processes Assisted by Chlorine

Every compound that potentially can be harmful to the environment is called a Contaminant of Emerging Concern (CEC). Compounds classified as CECs may undergo different transformations, especially in the water environment. The intermediates formed in this way are considered to be toxic against living organisms even in trace concentrations. We attempted to identify the intermediates formed during single chlorination and UV-catalyzed processes supported by the action of chlorine and hydrogen peroxide or ozone of selected contaminants of emerging concern. The analysis of post-processing water samples containing benzocaine indicated the formation of seven compound intermediates, while ibuprofen, acridine and β-estradiol samples contained 5, 5, and 3 compound decomposition by-products, respectively. The number and also the concentration of the intermediates decreased with the time of UV irradiation. The toxicity assessment indicated that the UV-catalyzed processes lead to decreased toxicity nature of post-processed water solutions.

Screen-printed electrodes-based technology: Environmental application to real time monitoring of phenolic degradation by phytoremediation with horseradish roots

The following is a description of a simple strategy for monitoring phenolic pollutants from highly-contaminated water samples. These phenolic compounds are removed from tap water using horseradish roots (Raphanus sativus) that contain peroxidase as catalyst and H₂O₂ to generate hydroxyl radicals. The later (^•OH) acts on the aromatic structure, causing them to degrade to non-toxic by-products. The tool used to follow up the evolution of the process is based on screen-printed carbon electrodes (SPCEs) as electrochemical sensor for simultaneous detection of hydroquinone (Epa at 0.047 V), m-cresol (Epa at 0.506 V) and 4-nitrophenol (Epa at 0.696 V) by differential pulse voltammetry (DPV). This electroanalytical methodology enables close monitoring of the situation and rapid sensor response time. Furthermore, this direct methodology works for opaque and heterogeneous samples, as tap water with chopped horseradish roots, without any treatment of samples previously to the analysis. For better knowledge of the electrodic-transfer process, the electrochemical behavior of these phenolic compounds by cyclic voltammetry (CV) is also included. This simple methodology shows a low detection limit (below to 5 μM) and an excellent selectivity (peak potential separation between them up to 200 mV or greater) in a linear range of three orders of concentration (from 1-5 μM to 1 mM) for all of the analytes studied. The DPV responses of the phenolic compounds during the phytoremediation process are simultaneously monitored by this direct, cheap, reproducible (RSD < 2.3%) and rapid DPV-SPCE electroanalytical methodology. Portable device as electrochemical sensor with this optimized and validated technology can be applied for decentralized analysis, on-site assays and rapid screening purposes. The use of the horseradish roots achieves the total elimination of phenolic pollutants in concentrations 1000 times higher than the legal limits in less than 1 h.

Nanoparticle-templated conversion of glucose to a high surface area biocarbon for the removal of organic pollutants in water

While extensive work has been done on the generation of adsorbents by carbonization of large polymeric structures, few works are currently available for the use of monomeric carbon molecules as precursors during carbonization. In this work we report the formation of a carbon adsorbent material from the carbonization of glucose in the presence of zinc oxide (ZnO) nanoparticle templates. Carbonization at 1,000 °C under inert atmosphere yields a product with Brunauer-Emmett-Teller (BET) surface area of 1,228.19 m²/g and 14.77 nm average pore diameter. Adsorption capacities against methylene blue, 2-naphthol and bisphenol-A at pH 7 were found to be 539 mg/g, 737 mg/g and 563 mg/g, respectively. Our material demonstrates a strong fit with the Langmuir isotherm, and adsorption kinetics show regression values near unity for the pseudo-second order kinetic model. A flow adsorption column was implemented for the remediation of tap water containing 20 mg/L methylene blue and found to quantitatively purify 11.5 L of contaminated water.

Identifying Plant-Based Natural Medicine against Oxidative Stress and Neurodegenerative Disorders

Free radicals and oxidative stress are among the most studied factors leading to the imbalance in mental health. With no exception, free radicals also damage neuronal cells, leading to various degenerative diseases. With existing modern medications, around 80% of the world population relies on herbal medicine for various ailments. Phytochemicals in plants have a wide range of pharmacological properties, the major being their ability to scavenge free radicals. Plant polyphenols are among the major class of antioxidants identified in plants. This antioxidative property of plant compounds and their ability to downgrade the process of oxidative stress can be used to treat neurodegenerative diseases. However, selecting plants and their active compounds is a crucial step in framing the mechanism of action underlying their therapeutic potential.

Method Validation and Investigation of the Levels of Pharmaceuticals and Personal Care Products in Sludge of Wastewater Treatment Plants and Soils of Irrigated Golf Course

The validation of a sensitive and reliable analytical procedure for the determination of pharmaceutical and personal care products (PPCPs) in solid environmental samples is reported in this study. Initially, two types of derivatization were used for the identification of the 13 target PPCP standards (acylation and silylation), but silylation proved to be better in sensitivity as it detected all of the analytes under investigation. Samples were extracted using an ultrasonicator, concentrated and re-dissolved in 100 mL water, then cleaned-up using C18 cartridges before silylation that preceded the Gas chromatography-mass Spectrometry detector (GC–MS) analyses. The optimized method provided a linear response over the range of 10–400 ng·g⁻¹ with r² > 0.992 and satisfactory recoveries (>45.6%) for the 13 compounds of interest. In this study, the variation of the sonication temperature, type of organic solvent for extraction, and types of cartridge were used to optimize the extraction procedure. A good repeatability (within day) and reproducibility (between days) with a relative standard deviation (RSD) that was equal or less than 13% for all the PPCPs were achieved with the developed extraction procedures for the irrigated soil and sewage sludge samples. The limits of detection (LODs) of the tested compounds varied from 0.1 ng·g⁻¹ (aspirin) to 1.4 ng·g⁻¹ (doxycycline) and from 0.1 ng·g⁻¹ (codiene) to 1.7 ng·g⁻¹ (doxycycline) for soils and sewage sludge samples, respectively. The method was successfully applied to the sludge of wastewater treatment plants and soils of an irrigated golf course. Among the tested emerging pollutants, paracetamol showed the highest concentration value of 98.9 ng·g⁻¹ in the sludge, and for the irrigated soil (0 to 10 cm), the concentration ranged from 1.16 ng·g⁻¹ (aspirin) to 8.57 ng·g⁻¹ (ibuprofen).

Distillery Stillage: Characteristics, Treatment, and Valorization

Distilleries are among the most polluting industries because ethanol fermentation results in the discharge of large quantities of high-strength liquid effluents with high concentrations of organic matter and nitrogen compounds, low pH, high temperature, dark brown color, and high salinity. The most common method of managing this wastewater (distillery stillage) is to use it for soil conditioning, but this requires thickening the wastewater and may cause soil pollution due to its high nitrogen content. Therefore, treatment of distillery stillage is preferable. This review discusses individual biological and physico-chemical treatment methods and combined technologies. In addition, special attention is paid to valorization of distillery stillage, which is a valuable source of polysaccharides and volatile fatty acids (VFAs), as well as natural antioxidants, including polyphenols and other bioactive compounds of interest to the pharmaceutical, cosmetic, and food industries. New directions in improvement of valorization technologies are highlighted, including the search for new eutectic solvents for extracting these compounds. Such technologies are essential for sustainable development, which requires the use of management and valorization strategies for recovery of valuable compounds with minimal disposal of waste streams.

UV-Catalyzed Persulfate Oxidation of an Anthraquinone Based Dye

Wastewater from the textile industry has a substantial impact on water quality. Synthetic dyes used in the textile production process are often discharged into water bodies as residues. Highly colored wastewater causes various of problems for the aquatic environment such as: reducing light penetration, inhibiting photosynthesis and being toxic to certain organisms. Since most dyes are resistant to biodegradation and are not completely removed by conventional methods (adsorption, coagulation-flocculation, activated sludge, membrane filtration) they persist in the environment. Advanced oxidation processes (AOPs) based on hydrogen peroxide (H2O2) have been proven to decolorize only some of the dyes from wastewater by photocatalysis. In this article, we compared two very different photocatalytic systems (UV/peroxydisulfate and UV/H2O2). Photocatalyzed activation of peroxydisulfate (PDS) generated sulfate radicals (SO4•−), which reacted with the selected anthraquinone dye of concern, Acid Blue 129 (AB129). Various conditions, such as pH and concentration of PDS were applied, in order to obtain an effective decolorization effect, which was significantly better than in the case of hydroxyl radicals. The kinetics of the reaction followed a pseudo-first order model. The main reaction pathway was also proposed based on quantum chemical analysis. Moreover, the toxicity of the solution after treatment was evaluated using Daphnia magna and Lemna minor, and was found to be significantly lower compared to the toxicity of the initial dye.

The potential of the organic micropollutants emission from swimming accessories into pool water

The potential leaching of organic micropollutants from swimming accessories was studied in the laboratory experiment. Seventeen different swimming accessories have been placed in various water matrices under different conditions in order to reproduce the actual environmental conditions of swimming pool water. The presence of micropollutants in water samples, after the exposure of swimming accessories, was assessed using indirect indicators (Total Organic Carbon and Phenol Index) and directly using a gas chromatograph coupled with a mass spectrometer with electron ionization. A wide range of organic compounds emitted from swimming accessories have been identified. The most common in tested samples was isophorone. The frequency of its occurrence in 50 swimming pools located in Poland was equal to 89% in concentrations ranged from 0.75 to 1.01 µg L^-1 (below the concentration of 40 µg L^-1, which is estimated to increase the cancer risk). Content of combined chlorine (1.52-3.16 mgCl₂ L^-1) in chlorinated matrices indicated a high potential for disinfection by products (DBPs) formation from organic matter emitted into pool water from swimming accessories. Ten of seventeen tested samples showed the toxic effect, measured as the bioluminescence inhibition of bacteria Aliivibrio fischeri.

Diet aid or aid to die: an update on 2,4-dinitrophenol (2,4-DNP) use as a weight-loss product

During the last decades, we have witnessed unparalleled changes in human eating habits and lifestyle, intensely influenced by cultural and social pressures. Sports practice became strongly implemented in daily routines, and visits to the gym peaked, driven by the indulgence in intensive 'weight-loss programs'. The pledge of boasting a healthy and beautiful body instigates the use of very attractive 'fat burners', which are purportedly advertised as safe products, easily available in the market and expected to quickly reduce body weight. In this context, the slimming properties of 2,4-dinitrophenol (2,4-DNP) galvanised its use as a weight-loss product, despite the drug ban for human consumption in many countries since 1938, due to its adverse effects. The main symptoms associated with 2,4-DNP intoxication, including hyperthermia, tachycardia, decreased blood pressure, and acute renal failure, motivated a worldwide warning, issued by the Interpol Anti-Doping Unit in 2015, reinforcing its hazard. Information on the effects of 2,4-DNP mainly derive from the intoxication cases reported by emergency care units, for which there is no specific antidote or treatment. This review provides a comprehensive update on 2,4-DNP use, legislation and epidemiology, chemistry and analytical methodologies for drug determination in commercial products and biological samples, pharmacokinetics and pharmacodynamics, toxicological effects, and intoxication diagnosis and management.

Sulfonated polyaniline-encapsulated graphene@graphitic carbon nitride nanocomposites for significantly enhanced photocatalytic degradation of phenol: a mechanistic study

The photocatalytic degradation of phenol through -s-PANI@g-C₃N₄ and its nanocomposites with graphene.

Recent advances in allelopathy for weed control: from knowledge to applications

Allelopathy is the biological phenomenon of chemical interactions between living organisms in the ecosystem, and must be taken into account in addressing pest and weed problems in future sustainable agriculture. Allelopathy is a multidisciplinary science, but in some cases, aspects of its chemistry are overlooked, despite the need for a deep knowledge of the chemical structural characteristics of allelochemicals to facilitate the design of new herbicides. This review is focused on the most important advances in allelopathy, paying particular attention to the design and development of phenolic compounds, terpenoids and alkaloids as herbicides. The isolation of allelochemicals is mainly addressed, but other aspects such as the analysis and activities of derivatives or analogs are also covered. Furthermore, the use of allelopathy in the fight against parasitic plants is included. The past 12 years have been a prolific period for publications on allelopathy. This critical review discusses future research areas in this field and the state of the art is analyzed from the chemist's perspective. © 2019 Society of Chemical Industry.

Enhanced degradation of 1-naphthol in landfill leachate using Arthrobacter sp

Arthrobacter sp. named as JY5-1 isolated from contaminated soil of a coking plant can degrade 1-naphthol as the sole carbon source. Through identification of species, analysis of the optimal degradation condition and kinetic equation, the degradation characteristic of Arthrobacter sp. JY5-1 was obtained. Later, the acclimated strain was added into the bio-reactor to observe treatment performance of landfill leachate. The results showed that the optimal conditions for strain JY5-1 biodegradation in the study were pH 7.0 and 30^oC. The bio-reactor operation experiment declared that Arthrobacter sp. JY5-1 had a strengthened effect on COD removal of landfill leachate. Moreover, the efficiency of COD removal could be high and stable when JY5-1 was accumulated as a biofilm together with active sludge. These results demonstrate that adding 1-naphthol-degrading strain JY5-1 is a feasible technique for the enhanced treatment of sanitary landfill leachate, providing theoretical support for engineering utilization.

Sorption Properties of Polydivinylbenzene Polymers towards Phenolic Compounds and Pharmaceuticals

Highly cross-linked polymers are commonly used in purification and separation techniques because of their many useful features. In order to better adjust their porosity to adsorption of specific compounds, methods like surface functionalization or imprinting are used. In this work, a series of highly cross-linked polydivinylbenzenes (pDVB) were prepared using a suspension method. Toluene was applied as a pore-forming diluent. Some part of toluene (1 mL) was replaced with phenol (F), 2,4,6-trichlorophenol (T) or their mixture (M) to prepare polymers with porosity more suitable for phenols sorption. Another approach was an introduction of sulfone groups onto the polymer surface (pDVB-SO3H). The physicochemical characteristics of the synthetized adsorbents included CHN, FTIR, DSC and porosimetric analyses. Afterwards, to evaluate sorption properties of the prepared adsorbents towards phenols, ibuprofen and salicylic acid the solid phase extraction (SPE) experiments were performed. The polymers had the specific surface areas of about 440–560 m2/g created mainly by mesopores with widths ca. 3.75 and 4.75–7.15 nm. Materials obtained with the addition of porosity modifiers (phenol, trichlorophenol, mixture) had more uniform porous structure and their sorption capacity toward phenols increased ca. 5%. Similar sorption capacities were obtained for ibuprofen. Salicylic acid had low affinity to the surface of the tested polymers.

Reduced graphene–tungsten trioxide-based hybrid materials with peroxidase-like activity

Hybrid material with enzyme-like function.